A major U.S. government laboratory is planning to dramatically reduce the number of chimpanzees it will use for biomedical research because “new scientific methods and technologies have rendered their use in research largely unnecessary.”

The National Institutes of Health (NIH) say it plans to keep, but not breed, 50 chimpanzees for biomedical research while retiring the rest. The chimpanzees that could be retired could eventually join more than 150 already in the Federal Sanctuary system, which was established in 2002.

NIH owns about 579 chimpanzees, of which 360 are now available for research. The others are retired or retiring.

“Americans have benefitted greatly from the chimpanzees’ service to biomedical research,” said NIH Director Dr. Francis S. Collins in a statement. “Their likeness to humans has made them uniquely valuable for certain types of research, but also demands greater justification for their use.

“After extensive consideration with the expert guidance of many, I am confident that greatly reducing their use in biomedical research is scientifically sound and the right thing to do,” Collins said.

According to the NIH, the chimpanzees that will be kept will be housed in “ethologically appropriate facilities,” with space requirements yet to be determined. It said it “will engage chimpanzee behavior and facilities experts to determine the appropriate minimum space requirement for research chimpanzees.”

Furthermore, a review panel would be established to consider research projects proposing the use of chimpanzees following Institute of Medicine (IOM) guidelines and principles.

Finally, the NIH says it will “wind down research projects using NIH-owned or supported chimpanzees that do not meet the IOM principles and criteria in a way that preserves the research and minimizes the impact on the animals.”